This invention pertains to the field of fiber processing at the stage of spinning preparation and is particularly concerned with the handling of sliver outputted by a sliver-producing machine, such as a carding machine or a drawing frame.
Conventionally, the sliver exiting at the output end of the sliver-producing machine is deposited in a coiler can by a sliver coiler which is arranged at the output end of the sliver processing machine and which has a rotary coiler head supported in a stationary coiler plate. The upwardly open coiler can is situated underneath the coiler head which has an eccentrically arranged sliver outlet, so that upon rotation of the coiler head the sliver outlet orbits in a circular path, resulting in an annular (coiled) pattern of the sliver as it is deposited into the coiler can.
The diameter of the circular path travelled by the sliver outlet provided in the coiler head is less than the maximum horizontal linear dimension of the coiler can so that, to ensure sliver deposition in the entire cross-sectional area of the can, the can is moved underneath the coiler head while the latter rotates. The coiler can may be of circular cross section, in which the case the coiler can platform on which the coiler can stands is rotated about an axis which coincides with the longitudinal can axis. If the coiler can is of flat configuration, that is, it has an elongated rectangular horizontal cross-sectional outline, the platform is moved back and forth parallel to the length (longer side) of the flat coiler can.
Also conventionally, the coiler can is provided with a vertically displaceable bottom which is gradually lowered as the can is being filled with sliver. During such a process, the underface of the stationary head plate in which the rotary coiler head is supported is in contact with the momentarily uppermost sliver layer and thus a certain compression force is exerted to the deposited sliver material. As a simple, conventional solution, a coil spring is provided which urges the can bottom upwardly and which yields to the increasing weight of the sliver and thus the can bottom is automatically lowered as the filling process progresses.
It is a desideratum that the sliver fill be of homogenous consistency throughout the can height and that the sliver deposition proceed in a stable manner. One condition for achieving such a result is to ensure that the extent of compression of the sliver in the coiler can, that is, the pressure exerted on the sliver by the cooperation between the can bottom and the coiler plate remains constant regardless of the fill level, that is, regardless of the momentary height position of the can bottom. Such a uniform pressure cannot be satisfactorily ensured by a coil spring which urges the can bottom upwardly and which yields under the pressure of the sliver supported on the can bottom.